Spreader stoker apparatus



25, 1945- A. F. SCHWENDNER 2,391,597

SPREADER STOKER APPARATUS Filed Sept. 21, 1944 Illlllllllllllil ||||l|| f INVENTOR Humour E SCHWENDNER.

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ATTORNEY Patented Dec. 25, 1945 SPREADER STOKER APPARATUS Anthony F. Schwendner, Ridley Park, Pa., as-

signor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 21, 1944, Serial No. 555,086

4 Claims.

' Thi invention relates to stokers, more particularly to those of the sprinkler or spreader" type wherein fuel fed to a rotary member is impelled by such rotary member to the fuel-supporting surface of a furnace grate, and has for an object to provide novel means for varying the trajectories of the fuel in traveling from the rotary impeller to the grate surface whereby the location of the area on which the fuel is deposited is correspondingly varied.

AnOther object of the invention is to provide, in a spreader stoker having a rotary impeller for sprinkling fuel onto a furnace grate through the atmosphere thereabove, means for automatically varying the rotative speed of the rotary impeller, whereby the trajectories of the fuel impelled thereby to the furnace grate are varied to deposit the fuel on different portions of said rate.

A further object of the invention is to provide, in a spreader stoker having a rotary impeller adapted to sprinkle fuel on a furnace grate through the atmosphere above the latter, a novel driving connection between the rotor and its driving motor, which connection includes mean for continuously varying the rotative speed of the impeller.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 i a vertical sectional view taken along the line 1-1 of Fig. 2, looking in the direction indicated by the arrows; and,

Fig. 2 is a plan view of the structure shown in Fig. 1, portions thereof being broken away for the sake of clearness.

Referring now to the drawing more in detail,

the reference character It) indicates, in its entirety, a stoker of the spreader or sprinkler type comprising a hopper II from which fuel is fed to the ram box I2, from which ram boX the fuel is pushed rearwardly by the rams l3, l4, l5 and It along the upper surface of a plurality of spill plates l1, l8, l9 and 20, to the rear discharge edges of the latter, for gravitational discharge therefrom to the rotary impeller 22, disposed therebeneath. Preferably, the rotary impeller 22 comprises a hollow drum or body portion 23 carrying a plurality of radially-extending fuel-impelling blades 24, adapted to project the fuel rearwardly through an opening in the front Wall of a furnace to the grate structure therein.

Any suitable means may be provided for imparting reciprocatory motion not only to the rams l3, l4, l5 and IE, but also, if desired, to the spill plates ll, 18, I9 and 20. The motion for the rams is derived from a suitable reciprocating engine 26, having a connection, at 21, with a reciprocable bar or rod 28, the latter being pivotally connected at 29 and 30 with the free ends of the crank arms 3i and 32, these crank arms being keyed, or otherwise secured, to Vertical shafts 33 and 34. Each of these vertical shafts carries a double cr nk arm, 35 and 35, the'free ends thereof being connected by links 31, 38, 39 and 40 to the rams l3, l4, l5 and [6, respectively. It will be obvious that, as the engine 26 reciprocates the bar or rod 28, oscillatory motion will be imparted to the vertical shafts 33 and 34, with consequent reciprocation of the links 31, 38, 39 and 40 and similarly of the rams l3, l4, l5 and H5 connected thereto.

Similar mechanism may be provided for imparting reciprocatory motion to the spill plates l1, l8, l9 and 20, such mechanism including double crank arms 42 carried by the lower ends of the vertical shafts 33 and 34 and connected at their free ends by links 43, having pivotal connections 44, with rods 45 secured to the various spill plates. Preferably, each link 43 is provided, intermediate its terminal portions, with suitable stroke-adjusting mechanism 46, whereby the length of the reciprocatory stroke of each spill plate may be adjusted to suit the particular operating conditions encountered.

Considering again the rotary impeller 22, the hollow. drum or body portion 23 thereof is supported by stub shafts 50 in bearings 5|. One of the stub shafts 50 is connected by suitable coupling means (not shown) with the driven shaft 52 of a conventional variable speed drive, indicated in its entirety by the reference character 53.

'In' the construction herein illustrated, the variable speed drive or transmission mechanism 53 comprises a pair of aligned pulleys having opposed flanges 54, 54 and 55, 55, provided with conical traction surfaces; conical" being used in the sense of a suitable convergent surface of revolution. The flanges are keyed to and slidable longitudinally on'shafts 56 and 52, respectively, which are journaled in bearings 51 secured to a frame 58.

A pair of double levers 59 are pivotally connected intermediate their ends, as at 60, to a rod or shaft 6| extending transversely of the frame, and located midway of the shafts 56 and 52. These levers are connected to the pulleys. 54 and 55, at 62, whereby pivoting of the levers about their f-ulcrums 50 effects longitudinal sliding movement of the pulley flanges on their respective shafts.

The levers 59 are threadedly connected, as at 63, to a shaft 64 having right-hand and left-hand threads 65 and. 66, respectively, and carrying at one end a gear 61, driven by a motor 68, by which the shaft may be rotated to effect pivotal movement of the levers.

Upon rotation of the shaft 54 "by the motor 68, the levers will be pivoted about their fulcrums 6| with the result that the pulley flanges 54 will be moved away from each other and the flanges 55 moved toward each other a corresponding distance, or vice versa, depending upon the direction of rotation of the shaft '64. "Power is transmitted to the shaft 56 from the main motor 69 and from the flanges 54 to the flanges 55 by a suitable belt 10, in a well-known manner.

A reversing relay, indicated in its entirety by the reference character ll, operates to periodically reverse the motor 68 When the shaft 54 has reached either limit of its rotation, whereby the drive ratio of the driving and driven pulleys is continuously varied. The reversing relay "H includes the usual relays l2 and 13 controlled by the snap switches 14 and. '1 5, respectively, for reversing the field of the motor 68 with respect to its armature, assuming that the motor 68 is of the D. C. type. The snap switches 14 and 15 are operated in response to movement of the levers 59 by suitable means, such as the lug or finger 15, carried by one of these levers and positioned so as to engage the snap switch 14 at one limit of its movement and to engage the snap switch 75 at the other limit of its movement. -A .main switch 11 is provided in the power line for starting and stopping the reversing relay mechanism H and the motor 68.

It is believed that the operation of the mechanism herein described will be obvious to those skilled in the art, but it is pointed out that, with the shaft 64 of the variable speed transmission mechanism 53 being'continuously operated by the motor 63 and its reversing relay 1!, the speedof the rotary impeller52 will be continuously varied through cycles with the result that the trajectories of the fuel impelled rearwardly thereby to the grate structure of the furnace will vary, due to the change in speed of the rotor, and the consequent change in impact of the blades 24 with the fuel, such changes in the trajectories "of the fuel resulting in corresponding variations in the point of deposit of fuel with respect to the frontto-rear dimensions of the grate structure. In other words, when the impeller 22 is rotating at its maximum speed, the fuel will receive relatively heavy impacts tending to throw it to the rearmost portion of the grate, while, when the rotary impeller speed is at its lowest, the impact rotary impeller.

of the blades against the fuel will be lighter, resulting in depositing of the fuel adjacent the front portion of the grate. Obviously, the intermediate speeds will result in depositing fuel at intermediate portions of the grate surface.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not solimited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In a stoker of the sprinkler or spreader" type, an impeller rotatable about a horizontal axis; a spill plate positioned with its rear discharge edge overlying said rotary impeller; means for feeding 'fuel rearwardly along said spill plate for discharge over the rear edge thereof to the rotary impeller therebeneath; a constant speed motor for rotating the impeller; and means acting between the motor and the impeller for automatically varying the speed of rotation of said impeller in cycles, whereby the trajectories of 'fuel leaving the impeller vary with consequent change in point of deposit of said fuel.

2. In a s'toker, a rotary impeller; a spill plate positioned with its rear discharge edge overlying said rotary impeller; means for feeding fuel rearwardly over said spill plate for discharge from the rear edge thereof to the rotary impeller therebeneath; a motor for continuously driving the'impeller; and mechanism acting between the motor and the impeller for automatically and continuously varying the rotative speed of the latter.

3. In a stoker, a rotary impeller; a spill plate positioned with its .rear discharge edge overlying said rotary impeller; means for feeding fuel rearwardly along said spill plate for discharge from the rear edge thereof to the rotary impeller therebeneath; a motor for driving said rotary impeller; variable speed mechanism providing a driving connection between said motor and the rotary impeller; and automatic means for continuously changing the setting of the variable speed mechanism, whereby the impeller speed is continuously varied with consequent changes in the trajectories of fuel leaving the impeller.

4. In a stoker, a rotary impeller; a spill plate positioned with its rear discharge edge overlying said rotary impeller means for feeding fuel rearwardly along said spill plate for discharge from the'rear edge thereof to the rotary impeller therebeneath; a driving motor for said rotary impeller; and means providing a driving connection between said motor and the rotary impeller, said last-mentioned means including mechanism providing continuous variation in the speed of the ANTHONY F. SCHWENDNER/ 

